InterviewSolution
Saved Bookmarks
| 1. |
The length of a tangent from a point A at distance 5 cm from the centre of the circle is 4 cm. Find the radius of the circle. |
|
Answer» Data: OB is the radius, BA is the tangent. ∴ ∠OBA = 90°, OA = 5 cm. (data) Length of tangent, AB = 4 cm. ∴ Radius, OB = ? In ⊥∆OBA, ∠OBA = 90° ∴ OB2 + BA2 = OA2. OB2 + (4)2 = (5)2 OB2 + 16 = 25 OB2 = 25 – 16 OB2 = 9 ∴ OB = 3 cm. ∴ Radius of circle, OB = 3cm. |
|